The present invention relates to a subcaliber kinetic energy projectile provided with a segmented discardable propelling cage sabot which encloses a partial region of the projectile which is provided with annular grooves on its outer surface for form lockingly engaging with annular countergrooves on the interior surface of the sabot.
U.S. Pat. No. 3,859,922 discloses a projectile arrangement which includes grooved teeth as the force transmitting means between a cylindrical propelling cage sabot and a projectile. For this purpose, the projectile or penetrator surface has been worked so that it has a structure of equidistant sawteeth. The inner surface of the propelling cage sabot is provided with corresponding sawtooth-like recesses into which engage the sawteeth of the penetrator surface. The steps of the propelling cage grooves are here slightly larger than those of the corresponding projectile grooves. Moreover, grooves are designed in such a manner that, before firing, the vertical flanks of the sawteeth of the projectile are not in direct contact with the corresponding vertical surfaces of the propelling cage sabot grooves, that small spaces exist between the vertical flank end surfaces which spaces become larger from tooth to tooth in the direction toward the tail. Only the surfaces of the foremost pair of teeth initially are in binding contact with one another. When a shot is fired, the relative deformation of the penetrator material and that of the propelling cage sabot material is intended to produce a successive closing of the spaces between the teeth starting with this foremost pair of teeth and continuing toward the rear teeth. The different sizes of the spaces between the teeth or ribs on the propelling cage sabot are provided to make the force transfer the same for each tooth or rib.
In this propelling cage sabot the force is transmitted only in the axial direction. Such a force transfer arrangement cannot be transferred to dual-flange propelling cage sabots since in the latter the space filled with gas pressure encounters not only axial forces but also radially acting forces, so that the displacement of the propelling cage sabot teeth as disclosed in U.S. Pat. No. 3,859,922 is not possible.
The artillery ammunition disclosed in U.S. Pat. No. 4,469,027 has right-hand and left-hand screw threads for the transmission of force between a propelling cage sabot and a projectile. In one embodiment, these threads are applied to two separate projectile sections. In a second embodiment, these threads are arranged above one another on one projectile section so that a type of herringbone pattern with rhombic projections is formed.
However, such form-locking threads in the sense of screw threads have the drawback that their production increases the notch sensitivity of the penetrator and this adversely influences the penetration process. Moreover, during cutting of a thread it frequently happens that the thread cutter employed goes out of true and, particularly if long threads are cut, pitch errors occur. The resulting inherent stresses generated during the separation of the sabot often cause the individual propelling cage sabot segments to be uncontrollably ejected.